When Mikki Kendall saw the news that Hermione Granger had been cast as a black woman in the upcoming play Harry Potter and the Cursed Child, she wasn't surprised. 

Before Emma Watson took on the role in the film adaptations of J.K. Rowling's books series, the Chicago writer had imagined the beloved magic-wielding bookworm as biracial. After all, she's described as having big, bushy hair, brown eyes and, at one point, "very brown" skin.

Not to mention, as a witch of non-magical lineage, Hermione is cruelly derided as a "mudblood" by the more bigoted of her "pureblood" schoolmates. Her description seemed the perfect allegory for being a child of mixed race. 

"It was weird when the movies were cast and it was a white girl," Kendall said. "Not like it couldn't be, but it just seemed that given all the focus in the early books on the texture of her hair and all of that mudblood thing, that it was going to be Rowling's nod to racial dynamics.   

"No one I know thought of Hermione immediately as being necessarily white."

Now, in this latest addition to the Harry Potter universe, she won't be.

Swaziland-born actress Noma Dumezweni takes on the iconic role in Harry Potter and the Cursed Child — a new London, U.K., play about the book's characters in their adult years. She has the full blessing of Rowling, who tweeted that she "loves black Hermione."

While the news may come as a shock for some who grew up watching Watson on screen, for many Harry Potter fans, the casting puts an official stamp on how they've always imagined Hermione.

'It means everything'

"I never thought this would actually happen, especially now. I thought I might see it when I was old and looking back at how bad the representation was at the turn of the century," New York writer and Harry Potter fan Alanna Bennett told CBC News.  "It's honestly one of the best things I've ever seen happen. It means everything."

As a biracial woman, Bennett said she's always identified with Hermione and her complex identity in the wizarding world. 

"The blood allegory in the books was one of the biggest things I remember using to understand my own ethnicity, especially through Harry and Hermione's experience with it. There was a duality in both of them that I really clung to as a biracial girl, and it was a language that was really useful for me," she said. 

Still, she always felt distanced from the character, who she thought of as white — until she discovered the myriad of online communities on sites like Tumblr and DeviantArt dedicated to fan-made art depicting Hermione as a woman of colour, and often as black. 

It's called "racebending" and it's one of the many tools that fans of sci-fi and fantasy use to reimagine their favourite fictional worlds to better reflect their own diversity.

"I think that what we're seeing a lot with fandom — and what's always been at the very heart of what fandom is — is the understanding that we don't have to settle," says Bennett, who wrote about the phenomenon on Buzzfeed.

"Hollywood may be lagging behind what we know we deserve to be able to see in our stories, but we don't have to settle for that. We can imagine characters as their best selves."

Reimagining characters diversely 

Nowadays, it's not just the fans who are reimagning their favourite characters. The entertainment industry is catching up.

Black actor Michael B. Jordan played The Human Torch in the latest Fantastic Four movie. Idris Elba has long been rumoured as the next James Bond. Lucy Liu plays Sherlock Holmes's Dr. Watson on CBS's Elementary.

Nowhere is this phenomenon more pronounced than in the comic book world. Women have taken on the mantles of both Thor and Captain Marvel. Muslim teen Kamala Khan is the new Ms. Marvel. Miles Morales, a teenager of black and Hispanic descent, has replaced Peter Parker as Spider-Man. The new Captain America is black

Christina Robins, a writer and activist living in Cambridge, Ont., says it's powerful for children to see themselves reflected in popular culture. 

"Of course, every race deserves to be represented and every kid needs to see themselves as important enough to represent," she said. "Hollywood erases so much culture."

Despite backlash, diversity sells

But not everyone has welcomed the news of a black Hermione. Many fans have taken to social media and the comments sections of news stories to deride the decision. 

"Black Hermione? Are you kidding? Makes no sense," one person tweeted. "I do not approve. Ruins all my mental images of the trio," wrote another.

There was a similar uproar when Elba was cast as the Norse gatekeeper Heimdall in 2011's Thor. There was even outcry when a black girl was cast as the character Rue in The Hunger Games film adaptation — despite the fact that she's described as black in the book. 

There were even calls to boycott Star Wars: The Force Awakens for casting black actor John Boyega as Stormtrooper-turned-hero Finn. 

Star-Wars-Boyega

John Boyega plays reformed Stormtrooper Finn in Star Wars: The Force Awakens. (Frazer Harrison/Getty Images)

"It's funny because these are all things where we can believe in dragons and giants and fairies and magic, but we can't believe in black people or Latinas or Middle Eastern people," Kendall said. 

Still, Thor earned $449.3 million at the box office and The Force Awakens crushed records on its opening weekend.

"You can't say that diversity is unnecessary when you see this money going somewhere else," says Kendall. "I'd like to believe it's also people being better humans, but I think at its base in any business model, cash is king. I mean, female Thor is doing quite well. Sure, the fanboys are mad about it, but oh well."